Acquired immunodeficiency syndrome-related progressive multifocal leukoencephalopathy-immune reconstitution inflammatory syndrome: prevalence, main characteristics, and outcomes in a Brazilian center

Background  Progressive multifocal leukoencephalopathy (PML) - immune reconstitution inflammatory syndrome (IRIS) in people living with HIV/AIDS (PLWHA) has been rarely described in low- and middle-income countries. Objective  To describe the prevalence of PML-IRIS among PLWHA with PML and its main features in a tertiary hospital in Brazil. Methods  We performed a retrospective cohort study. We included PLWHA with PML-IRIS patients admitted at Instituto de Infectologia Emílio Ribas , São Paulo, Brazil, between 2011 and 2021. We retrieved information on neurological manifestations, neuroimaging findings, treatments, and outcomes. Results  We identified 11 (11.8%) PML-IRIS cases among 93 patients with definite PML. Eight (73%) cases were men and had a median (IQR) age of 41 (27–50) years. Seven (63.6%) patients developed unmasking PML-IRIS and 4 (36.4%) had paradoxical PML-IRIS. The median (IQR) time from initiation of combined antiretroviral therapy (cART) to IRIS diagnosis was 49 (30–70) days. Ten (90.9%) patients received corticosteroids. There were 4 (36%) in-hospital deaths and 3 were associated with hospital-acquired pneumonia. Among the 7 (64%) patients who survived, 5 (71.5%) had sequelae at discharge. One year after the PML-IRIS diagnosis, 6 (54.5%) patients were alive. Conclusion  The prevalence of PML-IRIS was 11.8%. Most patients had unmasking PML-IRIS. In-hospital mortality and morbidity were high. One-year survival was similar to that described in some high-income countries.


INTRODUCTION
Progressive multifocal leukoencephalopathy (PML) is a demyelinating brain disease caused by the John Cunningham virus (JCV). 1,2It was first described in 1958 by Åström et al. 3 and finally associated to the JCV in 1971 by Padgett et al. 4 Before the human immunodeficiency virus (HIV) epidemic, PML was recognized as a very rare and fatal complication of either hematological malignancies or systemic inflammatory disorders.A literature review between 1958 and 1982 reported only 230 PML cases. 5In the precombined antiretroviral therapy (cART) era, HIV has become the most important underlying cause of immunosuppression in patients with PML.Previous studies indicate that 3 to 5% of people living with HIV/AIDS (PLWHA) present with PML, 6 with a 1year survival rate of 10%. 7n the cART era, an important incidence decrease of HIVrelated PML has been described, even though this reduction was lower than in other opportunistic diseases. 8,9In addition, the 1-year survival rate has increased to approximately 50% in PLWHA cases when using cART. 10,11espite the benefits of cART in the immune function and outcomes of PLWHA with PML, its use may cause an aberrant inflammatory response 12 named immune reconstitution inflammatory syndrome (IRIS). 13Progressive multifocal leukoencephalopathy-associated IRIS can be developed in two different settings: worsening of previously diagnosed PML after cART (paradoxical PML-IRIS) and de novo PML after initiation of cART (unmasking PML-IRIS). 14A systematic review and meta-analysis reported that 3 (16.7%)out of 52 HIV-related PML patients had IRIS and were classified as paradoxical IRIS. 15Another systematic review identified 46 cases of IRIS in HIV-related PML (21 unmasking PML-IRIS and 25 paradoxical PML-IRIS), 14 including 1 from Brazil 16 and 1 from Mexico. 17here is scarce information about PML-IRIS in PLWHA from low-and middle-income countries.In this study, we sought to estimate the prevalence of PML-IRIS among PLWHA with definite PML as well as to describe its main features and outcomes in a tertiary center in São Paulo, Brazil.

METHODS
We performed a retrospective cohort study including PLWHA patients with PML-related IRIS admitted at the There were 4 (36%) in-hospital deaths and 3 were associated with hospital-acquired pneumonia.Among the 7 (64%) patients who survived, 5 (71.5%) had sequelae at discharge.One year after the PML-IRIS diagnosis, 6 (54.5%) patients were alive.Conclusion The prevalence of PML-IRIS was 11.8%.Most patients had unmasking PML-IRIS.In-hospital mortality and morbidity were high.One-year survival was similar to that described in some high-income countries.

Resumo
Antecedentes A síndrome inflamatória de reconstituição imune (SIRI) da leucoencefalopatia multifocal progressiva (LEMP) em pessoas vivendo com HIV/Aids (PVHA) foi raramente descrita em países de baixa e média renda.The inclusion criteria were participants with: • confirmed HIV infection; [20] PML-IRIS was classified as: [20] Potential participants were retrieved from the databases of the Instituto de Medicina Tropical de São Paulo and the Instituto Adolfo Lutz, which were the reference laboratory centers in São Paulo where the qualitative CSF JCV-polymerase chain reaction (PCR) testing was performed.
Then, we screened the medical records of patients with detectable JCV in the CSF to identify cases fulfilling the criteria for definite PML.Finally, we selected the cases with PML-IRIS and obtained their demographic information as well as data regarding clinical presentation, neuroimaging findings, treatments, and clinical outcomes.All data were registered in a standardized electronic form.
Data for continuous variables were described with median and interquartile range (IQR), and for categorical variables as frequency and percentages.This study was designed and reported according to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines.
The present study was approved by the Scientific Division and the Ethics Committee of Instituto de Infectologia Emílio Ribas (Protocol Number 33/2022).

RESULTS
During the study period, 14,490 PLWHA patients were admitted to our institution, 93 (0.6%) of them fulfilled the criteria for definite PML, and 11 (0.08%) had PML-IRIS.Among the cases with PML, 11 (11.8%) had PML-IRIS and were included in the present study.Their median (interquartile -IQR) age was 41 (27-50) years, and 8 (73%) participants were men.Seven (63.6%) patients presented with unmasking PML-IRIS and 4 (36.4%) with paradoxical PML-IRIS.►Table 1 shows the main findings and outcomes of the patients included in this study, and ►Table 2 shows their main individual characteristics.
During hospitalization, 10 (90.9%) patients received corticosteroids and all of them maintained the use of cART.The median (IQR) length of hospital stay was 29 (11-54) days.There were 4 (36%) in-hospital deaths, 3 due to hospitalacquired pneumonia, and 1 to an unknown cause.Among the 7 (64%) patients who survived, 5 (71.5%) had sequelae at discharge.One year after the PML-IRIS diagnosis, 6 (54.5%) patients were alive and had a median (IQR) CD4þ T-cell count of 171 (161-201) cells/μL.All of them had HIV viral load 50 copies/mL.Two years after the PML-IRIS diagnosis, 6 (54.5%) patients were alive, and their median (IQR) CD4þ T-cell count was 237 (179-283) cells/μL, with 4 of them presenting HIV viral load 50 copies/mL.The other 2 patients had 11,812 copies/mL (case 1) and 17,183 copies/mL (case 9), respectively, but irregular use of cART was reported on their medical records.

DISCUSSION
In this study, the prevalence of PML-IRIS among PLWHA with definite PML, assessed in the context of a tertiary reference hospital, was 11.8%.There were 4 (36%) in-hospital deaths, three being associated with hospital-acquired pneumonia.Six (54.5%) patients were alive 1 year after the PML-IRIS diagnosis.
Immune reconstitution inflammatory syndrome is a common complication of cART initiation and is associated with considerable morbidity and mortality. 15,21Central nervous system (CNS) IRIS develops in 9 to 47% of PLWHA and is associated with a mortality of approximately 20 to 30%. 22requency and outcomes of IRIS vary widely depending on the underlying infection and on individual circumstances, 22 and cryptococcal and tuberculous meningitis are the most studied. 15ere, we identified a prevalence of PML-IRIS among PLWHA patients with definite PML of 11.8%.Several studies with heterogeneous criteria and design suggest that 4 to 42% of patients with HIV-related PML develop IRIS. 23ur sample's demographic and immunological profile before cART was similar to the results of the two main reviews on PML-IRIS, which mostly included patients from high-income countries. 14,18All of our patients were diagnosed with HIV infection before admission and most of them had a history of AIDS-defining disease, showing a current trend in the profile of hospitalized PLWHA.We identified a median time from initiation of cART to PML-IRIS diagnosis of  49 days, similar to the 35 to 53 days previously described. 14,18Interestingly, the immunological profile at PML-IRIS diagnosis was lower in our study (median CD4 T cell count ¼ 50 cells/μl) compared to the results of a prior review (median CD4 T cell count ¼ 101 cells/μl). 14Despite the limitations of this type of comparison, we can speculate that the lower immunological recovery observed in the short term in our study may be due, at least in part, to a longer period of immunosuppression before cART or to loss of follow-up.Loss of follow-up might happen because of various barriers hindering timely access to health systems, which are generally more relevant in low-and middleincome countries.Approximately 75% of our patients had unmasking PML-IRIS, similar to the 67% described in one study, 18 but considerably different from the 46% reported in another review. 14This discrepancy is probably explained by the different inclusion criteria used in these studies.Probably, the use of less stringent diagnostic criteria tends to result in higher rates of unmasking PML-IRIS, as reported in 72% of cases in a single center study. 20he diagnosis of IRIS in PLWHA is challenging.Several diagnostic criteria have been proposed, 15,[24][25][26] but the use of other definitions or unclear criteria is common in the literature. 15An interesting issue is the need to include increased CD4þ T-cell count as a criterion for IRIS.Shelburne et al.  (2002) considered the decrease in HIV viral load from baseline or an increase in CD4þ T-cell count from baseline. 24rench et al. ( 2004) considered an increase in blood CD4þ Tcell count after cART as a minor criterion of IRIS. 25 These recommendations consider that decreasing HIV viral load rather than rising CD4þ T-cell counts might be a more sensitive finding of IRIS. 13All PLWHA with PML-IRIS in this study were severely immunosuppressed, and their median CD4þ T-cell counts before cART and at PML-IRIS diagnosis were similar.A modest increase in CD4þ T-cell count at PML-IRIS onset was previously reported 14 and was comparable to the CD4þ T-cell counts observed in PML patients before the cART era. 19Another study showed that the rise in CD4þ Tcell counts from baseline to IRIS diagnosis was not statistically significant. 27In contrast, the rise of CD4 cell count over the first 3 months of cART was associated with IRIS. 28This finding suggests that longer time periods of observation may be needed to detect immunological changes associated with IRIS.Accordingly, 1 year after the diagnosis of PML-IRIS, the median CD4þ T-cell count in our surviving patients was 171 cells/μL, and all of them had undetectable HIV viral load.Thus, clinicians that suspect IRIS in the first months after the initiation of cART should be more attentive to the change in HIV viral load levels rather than to the CD4þ T-cell counts when using response to therapy as a diagnostic criterion. 13he diagnosis of PML-IRIS may be difficult since the diagnostic methods used (i.e., CSF JCV-PCR, brain MRI, consecutive HIV viral load) are expensive and not available in most resource-limited settings. 22,29A consequence of this scenario is the scarce information available on CNS-IRIS from low-and middle-income countries. 29,30For instance, prior to the present report, only 12 PLWHA with definite or possible PML-IRIS were reported in two studies conducted in Brazil. 31,32 this study, we used qualitative CSF JCV PCR information since this is the only data available in our assistance activities.In the cART era, a significant reduction in the diagnostic positive detection rate and in the predictive value of the negative test were observed. 33The immune reconstitution, represented by CD4 count above 100 cells/μl was demonstrated to be an independent predictor of failure to detect JCV DNA in the CSF of PML patients. 33In this context, monitoring the quantitative CSF JCV-PCR testing over time could be an indicator of PML-IRIS.
Despite the absence of controlled randomized trials demonstrating the benefit of corticosteroids in the treatment of CNS-IRIS, the fact that only observational evidence is available, 22,29,34 and the controversies about its use, 35,36 all but one of the patients of our sample received corticosteroids.
Survival of PLWHA patients with PML has improved in recent years.In the pre-cART era, only 10 to 35% of PLWHA patients were alive 1 year after the diagnosis of PML.8][39][40][41] However, this increase in PML survival is smaller than the one of more frequent opportunistic diseases. 38Inhospital mortality was high (36%) in our study and 3 of 4 cases were secondary to in-hospital pneumonia.In addition, survival 1 and 2 years after the PML-IRIS diagnosis was 54.5%.In contrast to our outcomes, a systematic review including 43 PLWHA with PML-IRIS mostly from high-income countries and followed for a median of 8 months reported that 72% of cases improved or stabilized within 2 years. 14Similarly, a study conduct in Spain including 18 PLWHA with PML-IRIS reported a PML a mortality attributed to PML of 22%. 20Different of these two studies, another review including 54 PLWHA with PML-IRIS mostly living in high-income countries reported a 1-year survival of 55.6%, 18 very similar to our results.Therefore, it is currently unknown whether the long-term outcomes of PLWHA with PML-IRIS are better in high-income countries than in middle-income countries, like Brazil.
Despite the improvement in survival observed in the cART era, PML continues to cause high morbidity.For example, a nationwide study reported 52% of progression of neurological symptoms or unchanged neurological symptoms in PLWHA with PML after four months of follow-up. 11We identified a higher rate (71.5%) of neurological sequelae at hospital discharge, suggesting an additional concern regarding patients who survive PML-IRIS.
In conclusion, the prevalence of PML-IRIS among PLWHA with definite PML was 11.8%.Clinical and laboratory baseline findings were similar to prior reports.However, the median CD4þ T-cell count was low at PML-IRIS diagnosis suggesting the relative value of this parameter in the definition of IRIS.The in-hospital mortality was high and all but one death were due to hospital-acquired pneumonia.The 1-year survival was similar to the one described in some studies performed in high-income countries.review and editing, software; ACM: writing review and editing; RMNM: data curation, formal analysis, writing review and editing, software; RAF: conceptualization, data curation, investigation, writing review and editing, software; JEV: conceptualization, formal analysis, methodology, project administration, resources, supervision, validation, writing-original draft, writing review, and editing.

Table 1
Main findings and outcomes of 11 people living with HIV/AIDS with PML-IRIS admitted at Instituto de Infectologia Emilio Ribas between 2011 and 2021 Abbreviations: cART, combined antiretroviral therapy; HIV, human immunodeficiency virus; IQR, interquartile range; MRI, magnetic resonance imaging; PML-IRIS, progressive multifocal leukoencephalopathy-immune reconstitution inflammatory syndrome; VL, viral load;.Note: a Proportion calculated out of 8 patients since one patient had a contraindication to the use of contrast (acute kidney failure).